1. Field of the Invention
The present invention is directed to a device for expanding liquefied gas with a separate vaporizing element.
The invention provides for an arrangement which allows the supply of liquefied petroleum gas (L.P.G.) for use in ignition engines normally receiving a liquid fuel.
It is suitable for all types of internal combustion engines, and it is adapted in particular to boat engines.
2. Description of the Prior Art
Liquefied petroleum gas is used more and more as a source of energy for motor vehicles. Indeed, this fuel has very interesting advantages, chief among which a very low pollution must be listed, and an advantageous charge rate used by numerous countries, allowing a substantial decrease in the kilometric cost.
The use of liquefied gas to operate an engine which was initially designed to receive a liquid fuel requires using a specific device ensuring the vaporization of the gas under a predetermined pressure and flow rate.
This device is usually in the form of a housing, generally made of a light metal cast iron, such as aluminum, and comprising a double enclosure formed of a gas vaporizing chamber and a thermal chamber in which a hot liquid circulates, which is most often constituted by the engine cooling water drawn due to a shunt made on the circuit connecting the latter to the radiator, or to the evacuation pipeline in the case of boat engines cooled with sea water. The two chambers have a common wall arranged to allow for the transmission of calories.
The vaporizing chamber also acts as a pressure regulator and, to this end, comprises a valve that is generally activated by an internal membrane.
The design of this system causes a certain number of drawbacks.
Given that the transfer of heat occurs through the wall that is common to the two chambers, and that the other walls of the vaporizing chamber communicate with the outside, substantial losses of calories occur, and in order to obtain a right vaporization of the liquefied gas, manufacturers have to provide separation walls in the form of a labyrinth in order to increase the common surface, which obviously generates high manufacturing costs. Despite these arrangements, it is necessary in certain cases to provide an additional heating means, for example, an electrical resistance as the one described in the Patent No. FR 2 759 419, or an outer impermeable enclosure provided with a heat supply element and connected to the thermal chamber of the vaporizing housing by a double canalization in a closed circuit, as one in which circulates a fluid ensuring the transfer of the calories produced in the heated enclosure toward the vaporizer, this device being the object of the Patent Application No. FR 98 08 110.
Furthermore, the existing apparatuses do not allow supplying high powered engines and, in this case, one must provide several steam pressure regulators for a single engine.